To find the median, your numbers have to be listed in numerical order from smallest to largest, so you may have to rewrite your list before you can find the median. The 'median' is the 'middle' value in the list of numbers. If you have the mean, but you’re missing one data point in your set, you could figure out the missing data point. The 'mean' is the 'average' you're used to, where you add up all the numbers and then divide by the number of numbers.
This is found by adding the numbers in a data set and dividing by the number of observations in the data set. Realize also that the formula for calculating the mean doesn’t allow you to find the mean only. Mean is the arithmetic average of a data set. If the mean were moved a bit left or right then the balance would tip one way or the other. In other words, it’s the point that would balance all of the distances between the points in the data set. And in that way, the mean represents the balancing point of all the data. What this tells us is that whenever we find the mean, what we’re really doing is creating a balance of distance between the points to the left and right of the mean. To be more specific, ?22? and ?26? are both ?2? units away from the mean and ?20? and ?28? are both ?4? units away from the mean.
We don’t really need the color coding, because the point we’re trying to illustrate is that we have an equal amount of distance from the mean on the left side as we do on the right side. We plotted ?20? and ?28? as gray dots, and ?22? and ?26? as orange dots.
